My son will be 17 on April, and he just decided one day not to talk with me and call be ***** everyday(everytime I ask him something or tell him to eat). He hasn't been eating a lot and after our trip back home he was still talking with me but after attending so many school activities and such... he has gone colder and colder. He hasn't talk with brother for about 9-10 months now... he decided not to to avoid one of those fights which he hated,and now me. I have not done a terrible thing but continue to encourage him to talk with his brother and just be nice... and try to get along.
I will never give up on him. He has no vice but playing piano... he is in gifted class... Great brains with very little emotion to the whole family.I told him he has to see a doctor but he said no... there is nothing wrong with him ,he just is not selling out with what other peoples belief and what should he be doing to his life must be on his own decision... and also now the brother who turned 18 is feeling depressed too... but don't want to talk with anybody. When I asked for help and referred to the doctor I learned that I can not forced him to go... unless he or my family is in danger... I think both needs to see the specialist... but the youngest(16) is getting so thin he needs it quickly... Please help.

I would talk to the teachers and see if you can get a better understanding of what's going on with them.
Then deal with accordingly. Don't automatically take the side of the teacher, or take as gospel, but should help.

Gifted, talented, 16 - 18 year olds can be withdrawn from parents. It's important to let them be young adults with their own life decisions without letting them disobey house rules. They may be not eating because you are too motherly about food (not your fault, of course - it just happens).

You write as though you might be from another culture, another country originally? Sometimes children also withdraw if they feel pressure from peers to be just like them, and they reject their parents. They will get over that, usually. Peer pressure among teens is intense, it's sort of a pack mentality, a gang, a family of their own as they transition from childhood to adulthood.

Can you ask for a time to talk? Do they sit down for dinner; can you say 'I'd like to talk at 7:30' and be firm about how concerned you are when you do talk. Talking is far preferable to calling for doctor visits at this stage. Let them know you love them the way they are, and what they chose to be.

Thanks Joy...
Not too motherly about food. They eat fine, just these weeks only did it changed.
I am thinking he might be confused of something's... and his relationship with his dad has gone from so so to sour.
Talking... done that... politely, civilly and formally with lots of assurance ,love and respect to them.
Both kids don't go out with a lot of friends/gang... they have both one good best friend who once in a while comes by to visit or sleep over... playing games,computer or watching movies.
It is my youngest that is most testy... and unruly<his word.

I try at least once a day but he just plays piano (self taught classically inclined playing such as CHOPIN)He has been in gifted class since Grade 4... like his brother. He is very analytic and black and white. He self taught most of what I would normally teach a child... from writing to reading and understanding how things work... but his EQ is just so straightforward cold most of the time... to me and his brother and other family members( I observed that when we visited back home).
I will try again... I never bothered him when he really is deep into his music.I will try again tomorrow.
Talking really does worked... and now it seems that this child of mine thinks he has grown better and right than his mom.
Thanks...

Teens need to think they know more than their parents. It's been this way for thousands of years.
It's how they prepare for being on their own, making decisions, and having confidence.
For most of those thousands of years, boys were adults by 13, out on the hunt with the men, having to wait at the back and do some of the menial work, but still out there being young men.
Our modern world is actually very disjointed and artificial and more difficult for teens in many ways.
They have a lot to fear right now, with careers and jobs so hard to find. So they take it out on those closest. Try to put up with some of it as long as they are good kids.